The ACRIMSAT Mission will measure Total Solar Irradiance (TSI) during its five-year mission life. The ACRIMSAT spacecraft,
carrying the ACRIM III instrument, will be secondary payload on a Taurus vehicle scheduled to launch in December 1999. The
instrument, third in a series of long-term solar-monitoring tools built for NASA by the Jet Propulsion Laboratory, will continue
to extend the database first created by ACRIM I, which was launched in 1980 on the Solar Maximum Mission (SMM) spacecraft.
ACRIM II followed on the Upper Atmosphere Research Satellite (UARS) in 1991.